This invention relates to the formation of fibers from attenuable material and while the invention is adapted for use in the formation of fibers from a wide variety of attenuable materials, it is particularly suited to the attenuation of various thermoplastic materials, especially mineral materials such as glass and similar compositions which are rendered molten by heating. As with the techniques of the prior applications Ser. No. 834,540 and Ser. No. 762,789, the present invention may be employed in connection not only with various mineral materials, but also with certain organic materials which are attenuable, such as polystyrene, polypropylene, polycarbonate and polyamides. Since the equipment or apparatus is especially useful in the attenuation of glass and similar thermoplastic materials, the following description refers to the use of glass by way of illustration.
Certain techniques for utilizing whirling currents or tornadoes for the attenuation of molten glass have been disclosed by us in prior applications above identified, such techniques being identified as toration. For example, U.S. Pat. No. 3,885,940, above identified, and also the companion U.S. Pat. No. 3,874,886, disclose development of pairs of counter-rotating tornadoes by directing a gaseous jet into a larger gaseous blast, thereby creating a zone of interaction including pairs of such tornadoes, and into which zone a stream of molten glass is delivered, with resultant attenuation of the glass stream.
In the equipment illustrated in said prior U.S. patents just mentioned, the orifice from which the glass stream is delivered to the zone of interaction is located at or adjacent to the boundary of the blast. In our prior application Ser. No. 557,282, now U.S. Pat. No. 4,015,964, toration arrangements are disclosed in which the glass orifice is positioned in spaced relation to the boundary of the blast, and in which the glass stream is delivered by gravity to the zone of interaction established by the interaction of a jet and a larger blast.
In prior applications Ser. Nos. 834,540, 762,789 and 676,755, both the glass orifices and the jet orifices are spaced from the boundary of the blast, and the glass streams are delivered by the action of the jets into zones of interaction of the jets with the blast. In the applications just mentioned, the glass streams are also subjected to two stages of attenuation, one stage occurring in the jet and the other in the blast.
Still further in our applications Ser. No. 834,540 and Ser. No. 762,789, the secondary or carrier jet which delivers the glass into the zone of interaction with the blast is caused to develop a stable zone of laminar flow lying between a pair of counter-rotating whirls or tornadoes, and the glass stream is delivered to the laminar zone and thereafter enters the region of the tornadoes of the carrier jet, which latter merge downstream of the carrier jet, but before the carrier jet reaches the principal blast. As is pointed out in our applications Ser. No. 834,540 and Ser. No. 762,789, the operation just described results in a two-stage attenuation, the first stage taking place as the glass stream is advanced into the influence of the tornadoes of the carrier jet, and the second stage taking place after the carrier jet and the partially attenuated stream is delivered into the zone of interaction of the carrier jet with the blast.
According to the disclosure of said applications Ser. No. 834,540 and Ser. No. 762,789, the zone of laminar flow and the tornadoes of the carrier jet are developed as a result of deflection of the carrier jet and, as further brought out, such deflection of the carrier jet contributes stability of operation, notwithstanding the delivery of the glass to the carrier jet at a point spaced from the principal blast. Numerous other advantages of these techniques are also pointed out in applications Ser. Nos. 834,540 and 762,789.
Various of the controls provided according to the present invention are applicable to any of the foregoing configurations of equipment for fiberization. In some of the configurations of the equipment, only three primary components are present in each fiberizing center, namely, the means for generating the jet, the means for generating the blast and the means for delivering the stream of attenuable material into the zone of interaction between the jet and the blast, but in the configuration of the equipment according to application Ser. No. 834,540 and Ser. No. 762,789, there are four components involved in each fiberizing center, including the three just mentioned, and also a device for influencing the jet flow.
Although various of the controls are applicable to and useful in equipment incorporating only the three basic components at each fiberizing center, certain of the controls of the invention are of special advantage where the fourth component is also present in each fiberizing center, for reasons which will appear more fully as this description proceeds.
It is a general objective of the present invention to provide novel arrangements for mounting the components of the fiberizing centers, including adjustable devices or controls for altering the relative effective operating interrelation between the several components of each fiberizing center, and especially for altering the angular and displacement interrelation or position of certain of the components with relation to the means for delivering the stream of attenuable material. This is of special advantage in installations adapted to the fiberization of thermoplastic mineral materials such as glass, particularly where the glass is supplied from a forehearth or other melting furnace. Indeed, in the preferred embodiment according to the present invention, most of the controls function in a manner to adjust the operating interrelation between one or more of the jet generator, the blast generator, and the means for influencing the jet flow (where this latter means is also present), with respect to the bushing or other apparatus employed for delivering a stream or streams of attenuable material from a melting furnace or other supply means for the attenuable material.
In providing for the controls referred to, it is also an objective of the invention to compensate for fluctuations in various operating conditions such as the temperature of the several components of the system, the composition and viscosity of the attenuable material, the velocities of the gases used for the jet and blast, and other variable operating conditions. Warpage or irregularities in the shape or dimensions of components may also be compensated for by use of the controls disclosed.
Although certain of the controls contemplated according to the invention are disclosed in a form in which temporary shut-down of the equipment would be required in order to make an adjustment, for the most part, it is contemplated according to the invention that at least most of the controls be capable of operation during fiberization and without shut-down of the equipment.
Having in mind that the various components of the fiberizing centers are relatively closely coupled to each other, it is also an objective of the invention to provide for automatic withdrawal or displacement of certain components away from the supply means for the molten material, in case of failure of the gas supply to at least one of the devices for generating the jet and the blast. In this way, damage to various components is avoided.